As the present electronic industry is developed rapidly, high-tech electronic products such as computer and communication products are introduced to the market constantly. In recent years, hand-held electronic communication products become a main development and all manufacturers try to improve their products by providing various lightweight, thin, short and compact designs and adopting multiple functions and powerful software applications to meet the consumer's increasing demand and lead the industry. Among all hand-held products, mobile phones, personal digital assistants (PDA) and Personal Handy-phone System (PHS) mobile phones are three most important products, since these products have multiple application tools (software), and each of the tools has many accessory tools (bundled software) with different functions. PDA is very popular and extensively accepted by people all over the world. As to electronic manufacturers, the way of designing a produce with a multiple of functions or a unique function at the lowest possible cost to meet the consumer requirements becomes an important index for evaluating the technological level of electronic manufacturers.
After the General Packet Radio Service (GPRS) is established, independent Global System for Mobile Communication (GSM) and Internet are integrated. The GPRS technology adds several data exchange nodes to the current existing global mobile communication system. Since the data exchange node has the capability of processing packets, the GSM can link with Internet.
Further, the transmission speed between a GPRS mobile phone and a base station can reach up to 160 Kbps, and the GSM phone can only have a speed of 9.6 Kpbs for transmitting data. The transmission speed of GPRS phones is 16˜17 times faster than that of GSM phones, and the speed of 160 Kbps is also 2 to 3 times faster than the 56 Kbps dial-up module. Thus, the transmission speed is improved greatly, and general computers can use the transmission speed of 56 Kbps to browse texts and graphics on the Internet. Of course, the GPRS phone also can send multimedia information including voices, graphics and texts.
As to the PHS phone, the Digital Cordless standard established by Japan is used; the transmission power of the base stations for mobile phones is usually below 32 W; the frequency ranges from 1895 MHz to 1918 MHz; and the PHS phone can dial or receive a call properly with a moving speed under 120 Km per hour. Compared with the high power mobile phones including the GSM900 and the DCS1800, the telephone fee of the PHS phone is much lower (about ⅓ of that of the GSM phone). Furthermore, the PHS phone has a low power consumption feature, no electromagnetic issue, a data transmission rate of 64 Kbps for broadband Internet access, an 800-hour idle time, and a capability of being plugged into an indoor phone line jack so as to have the function of a regular indoor phone. The PHS phone can be used at home, in the office and in the public area. The Japanese dual-mode technology allows users to maintain their original GSM phone number, while connecting their PHS phone to Internet for sending and receiving E-mails. One of the PHS service companies in Taiwan offers a “PHS Thumb Mail Service” that allows users to use a PHS phone to send and receive E-mails with an effect almost as convenient as a personal computer.
Since a general mobile phone only comes with one telecommunication service system, therefore users can only communicate with another mobile phone by one telecommunication service, and all other service systems are set aside and useless. Many mobile phone manufacturers and mobile phone accessory manufacturers developed a dual-mode mobile phone that can support both GSM and PHS. The dual-mode mobile phone can be switched freely between the GSM and PHS modules according to the environment and actual operation needs.
Although the dual-mode mobile phone has both GSM and PHS systems and is very convenient to users, users usually do not need to use both systems at the same time. Users use one of the systems at a certain time and a certain district. Furthermore, the cost of the dual-mode mobile phone is very high, and users usually will consider whether or not they really need such an expensive dual-mode mobile phone. The dual-mode mobile phone installs two different system chips and related components on a circuit board of the mobile phone, and the two system chips and related components occupy much space of the circuit board, so that the physical size of the circuit board cannot be reduced, and the lightweight, thin, short and compact design cannot be achieved, and the manufacturing cost cannot be lowered.